Dentures have long been used by patients for a variety of reasons. Modern dentures are relatively comfortable and not easily detectable. The process of being properly fitted for dentures typically requires numerous fittings and skill of the dentist. The typical process for being fitted for dentures requires a first trip by the patient for primary impressions to be made. A plaster model is formed from the primary impressions from which a custom tray is fabricated.
The patient then makes another trip to the dentist where a final impression using the custom tray is made. A working model in stone is fabricated from the final impression. A wax rim formed from the working model and provided to the dentist.
The patient makes a third trip to the dentist where the wax rims are marked up with data points, measurements, shades, etc. The marked up rims are mounted on an articulator to set the bite alignment and vertical spacing of the dentures. Teeth are selected from a library.
The selection and placement of the teeth is relatively subjective. Generally, the dentist or lab technician will select the teeth in accordance with a classification system that groups teeth into square, tapering, ovoid or combinations of each and relates them to facial outline. One example of such a system is known as the Williams Classification, and is derived from a theory that an inverted maxillary incisor tooth has the same general shape as the person's face. Different dentists or lab technicians will make different choices as to the choice of the tooth shape. Similarly, the shading of the teeth is also relatively subjective as well. The placement of the teeth in the denture base is also a subjective test, dependent upon the skill and experience of the technician. Normally, the lab technician will not have access to the patient or their history for determining the appropriate teeth and placement.
The teeth are set up in the wax rim. Occlusions are identified and the teeth are ground if necessary. The denture base with the full aesthetic wax up is delivered to the dentist.
The patient makes a fourth trip to the dentist for a try-in of the wax-up. The dentist looks at the bite, the speech, the shade, teeth position and the occlusions of the patient while the patient uses various jaw movements. If the dentist identifies any problems, the wax-up is sent back to the lab for additional changes. This process is repeated until the dentist and patient are satisfied.
Once the wax-up has been accepted, it is sent to the lab where a final wax-up is created. The borders are sealed out and the post dam is cased. A denture base is then created, usually by a flask molding process of investing the cast and the wax-up in a flask to make a mold that is used to form the denture base. The mold is then cured and divested from the flask. The denture is then processed by once again articulating the denture to check the bite. The denture is then analyzed and if passed, then undergoes a bulk trim. The denture then undergoes a final finish and polish. If the denture passes quality inspection it is sent to the dentist. The patient comes in for a fifth visit for a final try-in and delivery.
This process is time-consuming, requires multiple visits by the patient and multiple transmissions of data and models between the dental lab and dentist. The previous systems also require considerable skills of the dentist and the dental lab technicians. Additionally, each step along the process can lead to introduction of errors that must later be corrected.